Project Summary The burden of Human Papillomavirus (HPV)-related disease in the US is substantial. A safe and effective vaccine has been available for >10 years, yet the current rate of completion for the HPV series is only 49% for U.S.13-17 year olds. The Advisory Committee on Immunization Practices (ACIP) recommends routine HPV vaccination at age 11-12 years (yrs), but states that the vaccine ?can be given starting at age 9 years.? Currently, the majority of pediatricians begin recommending the vaccine at ages 11-12 yrs, however, a recent retrospective study showed that on-time completion rates for HPV vaccine were much higher when the vaccine series was initiated at ages 9-10 compared to ages 11-12 (adjusted odds ratio, 12.8). HPV vaccine should be given prior to sexual activity which occurs earlier than 13 yrs for many teens. There are compelling reasons to think that earlier initiation of vaccination at ages 9-10 might result in higher rates of acceptance of the vaccine and earlier series completion. First, many parents refuse HPV vaccine because they have concerns that vaccination could result in higher promiscuity in early adolescents if the vaccine is discussed in the context of sexuality. Initiation at 9-10 yrs, when few providers discuss sex, could put the focus squarely on cancer prevention, decreasing vaccine refusal. Second, three vaccines are recommended at the 11-12 yr visit, but many parents/adolescents are unwilling to receive all three at one visit. When one of the vaccines is delayed, it is almost always HPV vaccine. Initiation at 9-10 yrs when no other vaccines are given could result in less deferral of vaccination to mid-adolescence and higher rates of vaccination prior to early sexual activity. Finally, initiation at age 9-10 years has been shown to be feasible and, in an observational study, to result in higher rates of on-time series completion. Therefore, we plan to test the effectiveness of shifting initiation of HPV vaccine to 9-10 yrs in a randomized pragmatic trial. Our Specific Aims are to: SA 1: Recruit practices in two states (Colorado and California), randomize in a balanced fashion to recommending HPV vaccine at ages 9-10 yrs or 11-12 yrs and provide standardized training to both arms. SA 2: Conduct a trial to assess effectiveness of early initiation on the 1? outcome of age at HPV series completion; secondary outcomes will examine HPV series completion by age 13 and age at HPV series initiation. SA 3: Examine the effect of earlier initiation on length of time for HPV vaccine discussions and on parent/provider communication about HPV vaccine via audio-taping of visits, audio-elicitation interviews with parents and structured interviews with providers and clinic staff. If earlier HPV initiation is successful in promoting higher HPV series completion by 13 yrs, this intervention could be rapidly disseminated and would have the potential to prevent thousands of cases of HPV-related cancers, their attendant morbidity and mortality as well as the costs of screening, diagnosis and treatment for these cancers yearly.